Chromium promoted the efficient and stable catalytic degradation of propane over Pt/HZSM-5 catalyst: Optimization and reaction mechanism

Abstract

Light alkanes are a class of ubiquitous volatile organic compounds (VOCs), which bring great environmental hazards and health risks. However, low-temperature degradation of light alkanes is still a great challenge. Herein, a series of Pt/HZSM-5 catalysts without and with additives of Cr were fabricated. The catalytic performance of the catalysts for C₃H₈ low temperature combustion was investigated. It was found that Cr element had a significant effect on the activity of Pt/HZSM-5. Pt/Cr₁/HZSM-5 performed the best catalytic oxidation activity for C₃H₈, excellent high temperature stability and water resistance. Characterization results of catalysts indicated that the introduction of Cr element could fix Pt site to promote the dispersion of Pt on the support. Moreover, the interaction between Cr and Pt produced more active Pt species, surface active lattice oxygen and acidic sites, which could promote the activation of C–H bonds in C₃H₈. Theoretical calculations showed that the interface between Pt and Cr had stronger adsorption for O₂ and C₃H₈, which could accelerate propane oxidation. In this study, the effect of transition metal elements on the promotion of noble metal catalysts in the low-temperature degradation of light alkanes was discussed in depth, and it provided a reference for the design of efficient noble metal molecular sieve catalysts.